Joss Whedon is writing and directing the sequel, which reunites the main cast of Marvel's massive superhero team-up movie. The movie is also adding new actors and heroes to the fold, such as Elizabeth Olsen as the Scarlett Witch and Aaron Taylor-Johnson as Quicksilver.

Additionally, the main villain is a sentient artificial being known as Ultron, who will be played by James Spader.

Sources say that Kretschmann will play Baron Wolfgang von Strucker, an antagonist for both Captain America (Chris Evans) and Nick Fury (Samuel L. Jackson). In the comics, the man was a Nazi officer who becomes one of the heads of HYDRA, a terrorist organization.

Kretschmann's other credits include Peter Jackson's King Kong and Wanted with Angelina Jolie. He is also one of the stars of Stalingrad, the acclaimed Russian war movie that will be released on IMAX domestically in February.